code: 0xc0000005: read access violation at: 0x0, flags=0x0 (first chance)

[SPlatten]

I have a static const instance of QString defined in a class header, the class is called PSUApplication:

static const QString m_userDataRoot;
static const QString m_xmlFolder;

In the CPP file:

const QString PSUApplication::m_userDataRoot("./UserData");
const QString PSUApplication::m_xmlFolder(PSUApplication::m_userDataRoot + "xml/");

I have a references in other cpp files that use these statics to initialise other objects, such as QString's to make up references and QDir's.

These all fail at run-time. Is there a way to resolve this?

[SPlatten]

The problem doesn't exist when changing the types to char*.

[jsulm]

@SPlatten Can you show one of these failing initialisations?

Note: it is unusual to provide direct access to m_* fields as m_ usually is a prefix for private fields.

[J.Hilk]

Hi @SPlatten

like @kshegunov told me in my topic a long time ago:
https://forum.qt.io/topic/97838/static-const-qstring-implicit-sharing-issue/8

C++ does not guarantee you order of initialization of statics

so m_xmlFolder relies on m_userDataRoot which probably does not exist at that moment int time

[SPlatten]

I'm thinking that now if I was to change these to use basic data types like char[], it wouldn't be a problem. I'll try and report back.

[SPlatten]

The problem doesn't exist when changing the types to char*.

[J.Hilk]

@SPlatten said in code: 0xc0000005: read access violation at: 0x0, flags=0x0 (first chance):

The problem doesn't exist when changing the types to char*.

if the 2nd static variable is still depending on the first one, you will eventually run into trouble. Because the initialization order may now fit, but it could brake any moment.

[SPlatten]

I've changed these now, access functions are used to return QString's of the concatenated strings.